Dispatch calls generally use a forced-audio model where the target mobile station does not have to answer the call in order for the call to be set up. In other words, unlike traditional telephone systems, a dispatch call is set up at the time when the originator mobile station makes the call, assuming that the target mobile station is active. As a result, this can be extremely disruptive and intrusive for the user of the target mobile station, because the target mobile station automatically accepts the call without confirmation from the user. Some users try to work around this limitation by following a protocol that can be less intrusive. For example, the user of the originator mobile station may initiate a dispatch call with the user of the target mobile station without speaking, which may result in a “chirp” on the target mobile station. When the user of the target mobile station hears this “chirp,” the user can choose to either respond and engage in a conversation or send a “chirp” back to indicate that the user is currently busy and unable to talk. This behavior, however, is not enforced by either the mobile stations or the infrastructure and does not provide any reasons why the user of the target mobile station is unavailable. As a result, this may cause the user of the originator mobile station unnecessary frustration. Similarly, this can also be frustrating for the user of the target mobile station since there is no mechanism to prevent the user of the originator mobile station from speaking when the call is initially requested. Essentially, the users of a dispatch mobile station have very little control over their mobile station under such circumstances.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of various embodiments of the present invention. Also, common and well-understood elements that are useful or necessary in a commercially feasible embodiment are typically not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention.